261346591 has 4 divisors (see below), whose sum is σ = 285105384. Its totient is φ = 237587800.

The previous prime is 261346583. The next prime is 261346621. The reversal of 261346591 is 195643162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261346591 - 2³ = 261346583 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261346591.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261346531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11879380 + ... + 11879401.

It is an arithmetic number, because the mean of its divisors is an integer number (71276346).

Almost surely, 2^261346591 is an apocalyptic number.

261346591 is a deficient number, since it is larger than the sum of its proper divisors (23758793).

261346591 is a wasteful number, since it uses less digits than its factorization.

261346591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23758792.

The product of its digits is 38880, while the sum is 37.

The square root of 261346591 is about 16166.2175848279. The cubic root of 261346591 is about 639.3504077894.

The spelling of 261346591 in words is "two hundred sixty-one million, three hundred forty-six thousand, five hundred ninety-one".